Raspberry Pi that explains PWM control

Servo Motor Control using PWM with Raspberry Pi

Servos are controlled using a Pulse-Width Modulation (PWM) signal from the Raspberry Pi. PWM is a type of digital signal that allows us to control devices in an analog fashion. PWM varies the amount of time a signal is HIGH or LOW.
As a result, we get a variable signal that can be used to control the angle of a Servo motor. In this section, you’ll learn how to calculate the duty cycle for your servo motor using the datasheet. We’ll use the popular SG90 9g servo as an example; however, this methodology can be used for the majority of off-the-shelf servo motors.

 We have a tutorial using Raspberry Pi that explains PWM control  click here